1. Field of the Invention
The present invention relates to controlling a robot, and more particularly, to a method and apparatus for automatically allowing a mobile robot, which autonomously travels a predetermined space, to return to a docking station or a designated location when a predetermined job is completed.
2. Description of the Related Art
A variety of movable robots, which generally include a driving means, a sensor and a travel controller, and perform many useful functions while autonomously operating, have been developed. For example, a home cleaning robot is a cleaning device that sucks dust and dirt from the floor of a room while autonomously moving around the room without a user's manipulation. The home cleaning robot determines distances between furniture, office supplies, and walls in the room, which could be obstacles to its movement, by using its sensor or sensors and cleans the floor while controlling its movement based on the determined distances to avoid collision with any of the obstacles in the room. If the cleaning of the desired area is completed, the cleaning robot stops the cleaning work and at the same time stops the travel operation. As a result, the robot is left at a location distant from a predetermined location, for example, the robot is left at a location far from the docking station or designated location, such that the user frequently experiences various inconveniences. Accordingly, a technology by which after completing a predetermined job, a mobile robot, such as a cleaning robot, automatically returns to the docking station or a designated location is needed.
Among technologies for detecting the location of a mobile robot related to allowing a mobile robot to return to a docking station, there are Korean Patent Laid-open Publication Nos. 2000-66728 and 2002-33303, U.S. Pat. Nos. 6,338,013 and 6,138,063, and Japanese Patent Laid-open Publication No. 2000-56006. Korean Patent Laid-open Publication No. 2000-66728 relates to a robot capable of detecting a sound direction and a motion direction and with an intelligent function of automatic charge, and discloses an algorithm for the robot to return to an automatic charger by measuring the direction of sound. For this, if sound with a predetermined frequency is generated and output from a charger or the like, the robot detects the direction of the sound so that the robot can dock with the charger. This technology can measure and control only the direction of the robot. Korean Patent Laid-open Publication No. 2002-33303 relates to an apparatus for recognizing the location of a robot in a robot soccer game machine, and only the location of a robot is recognized by using a plurality of beacons. U.S. Pat. No.6,338,013 discloses a multifunctional, mobile appliance using a high precision positioning system capable of determining the location of a robot when the robot travels or stops. U.S. Pat. No. 6,138,063 discloses an apparatus which uses a gyrosensor to detect a direction angle so that a cleaning robot can autonomously modify the direction of travel and accurately arrive at a target location of travel. Japanese Patent Laid-open Publication No. 2000-56006 discloses a robot capable of accurately recognizing its location through a transmission and reception apparatus capable of communicating a predetermined signal with a fixed station.
However, the above-mentioned techniques are somewhat expensive to implement because they presuppose additional tools, such as a plurality of beacons or gyro-sensors, to recognize the location of a home cleaning robot or to detect directional angles.